Science and Tech GS Paper III (Space & Defence) by Rajvardhan Sir

Model Answer

Question #1. Remote Sensing Satellites have many advantages and applications in different fields. Elaborate. Also, Bring out the various remote sensing satellites launched by India and the various projects facilitated through them.
Approach:

• Briefly introduce remote sensing satellites (30 words)
• Advantages of the remote sensing satellites. Application of remote sensing satellites (50 words)
• India’s remote sensing satellites. Various remote sensing satellite projects taken in India (50 words)
• Conclusion (20 words)

Hints:

Remote sensing is deriving information about an object from a distance without physically coming into contact with the object. It is based on the principle that different objects have different radiation characteristics. It is useful for monitoring and assessment of natural resources etc, through the analysis of data obtained by observation from remote platform. The characteristics of an object can be determined by using reflected or emitted electro-magnetic radiation from the object. Actually each object has a unique and different characteristics of reflection or emission. Thus, remote sensing is a technology to identify and understand the object through the reflection or emission.

Advantages of remote sensing satellites

• The advantages of the satellite based remote sensing are its wide coverage, saving in time and tremendous cost effectiveness over other techniques.
• Large area coverage enabling regional survey of variety of themes and identification of large features.
• Repetitive coverage, allowing monitoring of dynamic themes like water, agriculture, etc.
• Data acquisition at multiple heights
• Data acquisition over inaccessible areas

Applications of remote sensing satellite

• By using these satellites land-use pattern can be mapped, it also helped in determining soil moisture and can estimate crop production.
• It helps in observing the flow of ocean currents and circulations.
• Studying glacier melts and effects on sea levels.
• It can help in tracking of displaced refugees
• It can help in monitoring active volcanoes using thermal remote sensing.
• It helps in measuring albedo for Earth’s radiation budget.

India’s remote sensing satellites

• Resourcesat -1 : For advanced applications like vegetation dynamics, crop yield estimates, disaster management support.
• Cartosat -1: For the preparation of cartographic maps, cadastral mapping updation, land use and GIS applications.
• Oceansat – 2 : To study surface winds, ocean surface strata, suspended sediments in the water.etc.
• Risat -2: India’s first satellite with SAR imager – all weather capability to take images of the earth.
• SARAL: satellite with Argos and ALtika to develop operational oceanography & forecasting capabilities.

Various remote sensing satellite projects taken in India

• Several remote sensing application projects have been carried out in the country under the National Natural Resources Management (NNRMS) of the Department of Space in coordination with central and state departments.
• Various remote sensing projects taken up in India are:
  • National waste land mapping
  • Land cover mapping
  • Agriculture drought mission
  • Forest cover mapping
  • Flood mapping
  • Project vasundhara
  • Environmental impact assessment....etc.

Conclusion:

Scientists use infrared images to determine the conditions of vegetation, survey temperature changes in water bodies, locate damage in underground pipelines, and map certain geographic features above and below the ground. The images from the satellites are used in the search for mineral and petroleum deposits. So, the remote sensing technology and remote sensing satellites have multiple applications and help in the social, political, economic, and environmental development of the country.

Question #2. India’s maiden human spaceflight program Gaganyaan is scheduled to be launched by 2023. In this regard, discuss the benefits and challenges of the program.

Approach:

•   Give a small introduction by mentioning about Gaganyaan project ( 20 words)
•   Mention the benefits of the program. Highlight its challenges (100 words)
•   Conclude (30 words)

Hints:

Gaganyaan is a fully indigenously designed autonomous 3.7-tonne spacecraft designed to carry a 3-member crew to orbit and safely return to the Earth after a mission duration of up to seven days by 2023 as a part of Indian Human Space lift Programme.   The space craft, which is being developed by ISRO consists of a service module and a crew module, collectively known as the orbital module. IROS GSLV Mk III, the three stage heavy lift launch vehicle, will be used to launch Gaganyaan as it has the necessary payload capability

Benefits of the program

•   This mission will play a significant role in enhancing, motivating and inspiring the upcoming young generations to take up science and research development in space technology of our country.
•   This project will source 60 % of its equipment from the Indian private sector hence this will spur the technological innovation.
•   This human spacelift programme will provide a unique micro gravity platform in space for conducting experiments and testing platform for future technologies.
•   Re-establish India’s role as a key player in the new space industry hence improving international collaboration and giving space to space diplomacy.
•   Gaganyaan programme will establish a broader framework for collaboration between ISRO, academia, Industry, National Agencies and other scientific organisations

Challenges of the program

• Rockets are extreme machines which will push your speed from 0 kmph to 29,000 kmph in less than 30 minutes. Many things can go wrong during the launch phase, including the rocket exploding into a fireball. Many safety features have to be built into rocket systems to ensure the probability of loss of life is minimized. However, testing of all these systems in an actual operating environment is next to impossible and a calculated risk has to be taken while embarking on such a mission.
• In space stations, astronauts receive over ten times the radiation than what people are subjected to on Earth. Radiation exposure may increase the risk of cancer. It can damage the central nervous system. Radiation can also cause nausea, vomiting, anorexia, and fatigue.
• India lacks training facilities for astrnauts, though ISRO has demanded for indigenous training centers for its astronauts since early 2000’s, no action have been taken yet.
• Transitioning from one gravity field to another is tricky. It affects hand-eye and head-eye coordination. Nasa has learned that without gravity working on the human body, bones lose minerals. Even after you return from a space mission, you could be at greater risk of osteoporosis-related fractures. If you do not exercise and eat properly, you will lose muscle strength. You might also develop vision problems.
• In addition to the lack of gravity and danger of radiation, there is no atmosphere. Human blood starts boiling if there is no pressure. The ‘Gaganyaan’ has to create an atmosphere like Earth inside a small volume and ensure that an adequate supply of oxygen, removal of carbon-dioxide and comfortable temperature and humidity levels are maintained throughout the mission.

Conclusion:

International Organisations and National Organisations were working hard to make Gaganyaan mission Successful; they were forcing to meet/tackle the above-mentioned challenges. When Indian is launched into space, the whole nation will be up there with them too.